Systems, devices, and method for the treatment of osteoarthritis

ABSTRACT

The present disclosure describes devices, methods and systems for modifying or altering gait kinematics via sensory augmentation and/or modifying muscle activation patterns via augmented motor learning to slow the progression of and/or reduce the pain associated with knee OA, particularly during gait (e.g., walking, running, stair climbing, etc.). Sensors can be used to measure gait parameters and characteristics and muscle activation patterns. Stimulation can be provided to the individual in order to promote learning new gait kinematics and muscle activation patterns.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/199,965, filed Jul. 31, 2015, and U.S. Provisional Application No. 62/276,797, filed Jan. 8, 2016, each of which is herein incorporated by reference in its entirety.

This application may be related to International Patent Application No. PCT/US2014/012388, filed Jan. 21, 2014, International Patent Application No. PCT/US2015/033809, filed Jun. 2, 2015, and PCT/US2016/037080, filed Jun. 10, 2016, each of which is herein incorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

FIELD

Embodiments of the invention relate to the treatment of osteoarthritis, and more particularly to gait retraining and/or modifying muscle activation patterns to treat knee pain associated with osteoarthritis.

BACKGROUND

Osteoarthritis (OA) is the most common form of arthritis, and both prevalence and incident rate increase with age. In the US, for adults over 30, symptomatic knee OA affects about 6% of the population. For ages 63-75, prevalence of knee OA increases to 11% of women and 7% of men. Pain in the knee due to a disease such as OA can have great functional impact and, especially among older adults, often reduces ability in activities of daily living (ADL) involving the legs, such as walking, transferring, and using the bathroom. OA causes more disability in walking and climbing stairs than any other disease and is the most common reason for total knee and hip replacement.

General knee pain has an even greater healthcare and societal impact. Two surveys assessing knee pain in older adults in the UK both estimated an annual prevalence of 25% for knee pain in older adults. In one of those studies, 15% of subjects in the general population aged over 55 have had restricted activity because of knee pain occurring on most days in one month during the past year.

In knee osteoarthritis, the medial compartment of the knee is affected ten times more often than the lateral compartment, which is likely due to greater medial compartment loading during gait to maintain knee joint stability. The first peak of the external knee adduction moment (KAM) is a surrogate measure of medial compartment loading, and has been correlated with pain and presence, severity, and progression of medial compartment knee osteoarthritis. Thus, treatments that reduce the KAM have the potential for reducing pain and slowing progression of osteoarthritis.

SUMMARY OF THE DISCLOSURE

The present invention relates to the treatment of knee pain associated with osteoarthritis, and more particularly to gait retraining and/or modifying muscle activation patterns to treat osteoarthritis.

The recent advances in the miniaturization of sensors, power sources, and stimulators, makes it possible to combine: (1) a feedback or cuing system to monitor an individual's gait kinematics and assist the individual in altering their gait by providing real-time feedback to the individual (e.g., visual, auditory, electrical, vibrational, etc.) without the need to visit a motion analysis laboratory, (2) an electrical nerve stimulation device that stimulates nerves around the knee from the skin surface to reduce the pain associated with OA, and/or (3) an electrical muscle stimulation device that alters muscle activation patterns based on measured EMG signals. There are four major challenges for providing effective feedback for gait modification; first, is to determine who may benefit from a gait change; second, determine the gait variable and target that will benefit an individual user ; third, to accurately measure important gait variables and provide sensory feedback and/or stimulation to promote a more biomechanically effective walking pattern; and fourth, to effectively alter muscle activation patterns to reduce knee loads that have a chronic, long-term effect by initiating plastic adaptation of central neural circuits and/or reflex pathways associated with gait.

There are also two major challenges for surface stimulation; first, stimulating at the amplitudes required to effectively stimulate these deep nerves may cause pain or discomfort due to the stimulation of the cutaneous receptors; second, neuroanatomical variability between individuals make it difficult to appropriately position the stimulation electrodes from the surface. This system for reduction of knee pain can increase the exercise tolerance of an individual with knee OA, which could lead to increased knee strength, improved joint stability, and further reduction in knee pain.

In some embodiments, a system for reducing knee pain associated with osteoarthritis in an individual is provided. The system can include a wearable sensor for measuring a gait parameter, and a therapy device in communication with the wearable sensor. The therapy device can be configured to deliver a sensory stimulation based on the measured gait parameter that is configured to alter the individual's gait, where the sensory stimulation has a stimulation parameter that is proportional to a deviation of the measured gait parameter from a set range or value for the gait parameter.

In some embodiments, the sensory stimulation is electrical and is configured to not induce contraction of a muscle. In some embodiments, the electrical sensory stimulation is configured to enhance motor plasticity.

In some embodiments, the sensory stimulation is tactile or auditory.

In some embodiments, the sensory stimulation is configured to be provided in a fading feedback manner.

In some embodiments, the wearable sensor comprises an IMU or a force sensor.

In some embodiments, the gait parameter is foot progression angle, toe angle, ankle plantar flexion angle, step width, knee flexion angle, knee adduction angle, or knee adduction moment, knee flexion moment, or ankle plantar flexion moment, or any combination of these gait parameters.

In some embodiments, the wearable sensor and/or therapy device comprises a knee band, ankle band, leg band, sock, knee brace, knee wrap, foot wrap, ankle brace, knee brace, ankle wrap, shoe, shoe attachment, insole, compliant patch, pants, leg sleeve, knee sleeve, or ankle sleeve.

In some embodiments, a system for reducing knee pain associated with osteoarthritis in an individual is provided. The system can include a wearable EMG sensor for measuring an activation of a gastrocnemius muscle, and a therapy device in communication with the wearable EMG sensor. The therapy device can be configured to deliver a sensory stimulation based on the measured activation of the gastrocnemius muscle, where the sensory stimulation is configured to inform the individual of the activation of the gastrocnemius muscle.

In some embodiments, the system further includes a second EMG sensor for measuring an activation of a soleus muscle, where the wearable therapy device is configured to deliver a second sensory stimulation based on the measured activation of the soleus muscle, where the second sensory stimulation is configured to inform the individual of the activation of the soleus muscle.

In some embodiments, the system further includes a wearable sensor for measuring a key gait event.

In some embodiments, the gait event is selected from the group consisting of foot strike and toe off.

In some embodiments, the therapy device is configured to deliver a stimulation configured to reduce the activation of the gastrocnemius muscle.

In some embodiments, the therapy device is configured to deliver the stimulation based on the measured gait parameter.

In some embodiments, the therapy device is configured to deliver a stimulation configured to enhance the activation of a soleus muscle.

In some embodiments, the therapy device is configured to deliver the stimulation based on the measured gait parameter.

In some embodiments, a system for reducing knee pain associated with osteoarthritis in an individual is provided. The system can include a wearable sensor for measuring a gait parameter, a wearable EMG sensor for measuring an activation of a gastrocnemius muscle, and a therapy device in communication with the wearable sensor and the wearable EMG sensor. The therapy device can be configured to deliver a first sensory stimulation based on the measured gait parameter that is configured to alter the individual's gait and a second sensory stimulation based on the measured activation of the gastrocnemius muscle, where the first sensory stimulation has a stimulation parameter that is proportional to a deviation of the measured gait parameter from a set range or value for the gait parameter, and where the second sensory stimulation is configured to inform the individual of the activation of the gastrocnemius muscle.

In some embodiments, the therapy device is configured to deliver a third stimulation configured to reduce the activation of the gastrocnemius muscle.

In some embodiments, the therapy device is configured to deliver a fourth stimulation configured to enhance the activation of the soleus muscle.

In some embodiments, a system for reducing knee pain associated with osteoarthritis in an individual is provided. The system can include a wearable sensor for measuring a gait parameter, a wearable EMG sensor for measuring an activation of a soleus muscle, and a therapy device in communication with the wearable sensor and the wearable EMG sensor. The therapy device can be configured to deliver a first sensory stimulation based on the measured gait parameter that is configured to alter the individual's gait and a second sensory stimulation based on the measured activation of the soleus muscle, where the first sensory stimulation has a stimulation parameter that is proportional to a deviation of the measured gait parameter from a set range or value for the gait parameter, and where the second sensory stimulation is configured to inform the individual of the activation of the soleus muscle.

In some embodiments, the therapy device is configured to deliver a third stimulation configured to enhance the activation of the soleus muscle.

In some embodiments, the therapy device is configured to deliver a fourth stimulation configured to reduce the activation of the gastrocnemius muscle.

In some embodiments, the therapy device is wearable.

In some embodiments, the therapy device is a mobile phone or smart watch.

In some embodiments, a method for reducing knee pain associated with osteoarthritis in an individual is provided. The method can include measuring a gait parameter; determining a deviation of the measured gait parameter from a set range or value for the gait parameter; delivering a sensory stimulation to the individual based on the determined deviation of the measured gait parameter; and altering the individual's gait kinematics such that the deviation of the measured gait parameter is reduced in subsequent measurements of the gait parameter.

In some embodiments, the gait parameter can be foot angle, step width, knee angle, and knee adduction moment.

In some embodiments, the set range or value is predetermined.

In some embodiments, the sensory stimulation is delivered in a fading feedback manner.

In some embodiments, the sensory stimulation is electrical and is configured to not induce contraction of a muscle.

In some embodiments, the electrical sensory stimulation is configured to enhance motor plasticity.

In some embodiments, the method further includes measuring an activation of the gastrocnemius muscle; and delivering a second sensory stimulation based on the activation of the gastrocnemius muscle to inform the individual of the activation of the gastrocnemius muscle.

In some embodiments, the method further includes measuring an activation of a soleus muscle; and delivering a third sensory stimulation based on the activation of the soleus muscle to inform the individual of the activation of the soleus muscle.

In some embodiments, the method further includes delivering a stimulation configured to reduce an excitability of the gastrocnemius muscle.

In some embodiments, the method further includes delivering a stimulation configured to enhance an excitability or activate a soleus muscle.

In some embodiments, the method further includes measuring an activation of the gastrocnemius muscle; measuring an activation of a soleus muscle; delivering a second sensory stimulation based on the activation of the gastrocnemius muscle to inform the individual of the activation of the gastrocnemius muscle; delivering a third sensory stimulation based on the activation of the soleus muscle to inform the individual of the activation of the soleus muscle;

delivering a stimulation configured to reduce an excitability of the gastrocnemius muscle; and delivering a stimulation configured to enhance an excitability or activate a soleus muscle.

In some embodiments, a method for reducing knee pain associated with osteoarthritis in an individual is provided. The method can include measuring a plurality of gait parameters;

determining a deviation of each of the measured gait parameters from a set range or value for each of the gait parameters; prioritizing the plurality of gait parameters based on the determined deviations; identifying a high priority gait parameter based on the step of prioritizing the plurality of gait parameters; delivering a sensory stimulation to the individual based on the high priority gait parameter; and altering the individual's gait kinematics.

In some embodiments, the sensory stimulation is delivered to a peripheral nerve in the leg.

In some embodiments, the sensory stimulation is delivered to a sensory nerve in the leg.

In some embodiments, a method for reducing knee pain associated with osteoarthritis in an individual is provided. The method can include measuring a plurality of gait parameters;

measuring activation of the gastrocnemius muscle; determining a deviation of each of the measured gait parameters from a set range or value for each of the gait parameters; prioritizing the plurality of gait parameters based on the determined deviations; identifying a high priority gait parameter based on the step of prioritizing the plurality of gait parameters; comparing the identified high priority gait parameter with the measured activation of the gastrocnemius muscle;

delivering a sensory stimulation to the individual based on the comparison of the high priority gait parameter with the measured activation of the gastrocnemius muscle; and altering the individual's gait kinematics or muscle pattern activation.

In some embodiments, the stimulation parameter is amplitude, frequency, pulse width, duration, or waveform shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

FIG. 1 is a schematic diagram illustrating some embodiments of a system to modify human gait kinematics and/or modify muscle activation patterns.

FIGS. 2A-2F illustrates an embodiment of a wearable system and device.

FIG. 3 illustrates another embodiment of a wearable system and device.

FIG. 4 illustrates an embodiment of a system and device that can be embedded or integrated into a shoe.

FIG. 5 illustrates an embodiment of an electrode array.

FIG. 6 illustrates another embodiment of a system and device that can be embedded or integrated into a shoe.

FIG. 7 illustrates an embodiment of the system and device with a dispensable conductive gel that can include a medication.

FIG. 8 illustrates another embodiment of an electrode array that can be made from a crossweave fabric.

FIG. 9 illustrates an embodiment of a flexible device that can be affixed to a body part.

FIG. 10 illustrates another embodiment of a flexible device that has a flexible substrate that conforms to the body.

FIGS. 11A-11C illustrate various embodiments of the system device being worn on various body parts.

FIG. 11D illustrates an embodiment of a patch device.

FIG. 12 illustrates an embodiment of a system and device with an array of effectors.

FIG. 13 illustrates a flowchart of an embodiment of a method to determine various gait parameters.

FIGS. 14A-14D illustrate various techniques for determining various gait parameters.

FIG. 15 illustrates various embodiments of a device inserted into the sole of a shoe.

FIG. 16 illustrates the mechanics of the foot during gait.

FIGS. 17A and 17B illustrate embodiments of responsive feedback and fading feedback.

FIG. 18 illustrates an embodiment of the system and device where the therapy unit and sensor unit are incorporated into a single wearable device.

FIG. 19 illustrates a way to determine foot orientation from a foot pressure map.

FIG. 20 illustrates another embodiment of a system and device that has been integrated into a shoe.

FIG. 21 illustrates knee load during walking.

FIGS. 22A-22C illustrates various muscles in the leg that are used during walking that can contribute to knee load.

FIGS. 23A and 23B illustrate the reduction in knee load from applying embodiments of the therapy described herein.

FIGS. 24A-24H illustrate various locations on the body that can be target by the systems and devices described herein.

DETAILED DESCRIPTION

“Electrical stimulation” refers to the application of electrical signals to the soft-tissue and nerves of the targeted area. Applying a “vibrotactile stimulation” refers to the application of a vibrational load to the soft-tissue and nerves and mechanoreceptors of the targeted area.

The systems, devices, and methods of this disclosure each have several innovative aspects, no single one of which is necessarily solely responsible for the desirable attributes disclosed herein. The present disclosure describes devices, methods and systems for (1) modifying or altering gait kinematics (or motion) via sensory augmentation and/or (2) modifying muscle activation patterns via augmented motor learning to slow the progression of and/or reduce the pain associated with knee OA, particularly during gait (e.g., walking, running, stair climbing, etc.). In some embodiments, peripheral nerve stimulation is used in conjunction with monitoring gait kinetics and kinematics and/or muscle activations, and providing real-time feedback to the individual. In some embodiments, a device is provided. Individuals with OA may have reduced proprioception and may therefore benefit from sensory augmentation therapies.

Additionally, repeated practice or exercise of a movement has been shown to elicit a plastic effect on in the brain, specifically in motor cortex. Repeated practice or exercise can be timed with electrical stimulation of specific nerves, muscles, reflex pathways, and/or motor cortex to enhance or accelerate the plastic effect. Thus, having an individual modify their gait kinematics in a specific, repeated practice can have lasting effect on gait patterns by retraining existing neural pathways in motor cortex or other parts of the central nervous system. To utilize this plastic change for the reduction of pain due to OA, a device will need to be sufficiently accurate and provide sensory feedback about specific gait variables to the individual at each step during the gait motion. This type of portable, wearable gait retraining system has not been possible in the past due to challenges in size, cost, and accuracy of sensors, especially portable, wireless sensors, power sources, and processors.

Stimulation applied to nerves and/or muscles can affect gait in multiple ways:

First, by direct muscle stimulation, when electrical stimulation is applied above muscle contraction thresholds and targets efferent nerves that innervate muscle or target muscle directly, this causes the muscle to contract and generate force to affect movement, similar to functional electrical stimulation (FES).

Second, by muscle re-patterning, stimulation is applied to afferent or sensory nerves that innervate muscle below muscle contraction threshold but above stimulation threshold of nerves; neuronal activity propagates to reflex circuits, like H-reflex, as well as back to the brain, especially motor cortex, and the central nervous system, causing plastic changes in the excitability of neural circuits and/or the muscles that drive regular gait patterns. Muscle re-patterning thus trains the wearer to transfer activation, and force, from one muscle (e.g., gastrocnemius) to another muscle (e.g., soleus) to unload the medial compartment during gait.

Third, by sensory augmentation, stimulation signals are applied to afferent or sensory nerves to lead a person to correct the motion causing pain. In OA, there is a delay between when a person performs the motions that overload the knee and experiences the resulting pain. Sensory augmentation uses sensory feedback to passively provide feedback to the central nervous system that causes someone to correct their motion. For example, in knee pain associated with OA, affectors may be positioned on the bottom or sides of the foot along the femoral and tibial distributions to provide sensory feedback to toe-in or toe-out. This may be less mentally taxing than cuing, and also more efficiently entrain sensory-motor circuits to produce motor plasticity in limb cortical areas. The electrical stimulation of the sensory nerves may also lead to stimulation of limb cortical areas of the brain that enhance motor plasticity and help an individual learn a new gait more quickly.

The device and system can use one or any combination of the above concepts to modify a person's gait to reduce pain and progression of OA.

Systems and Devices for Treating OA

Error! Reference source not found. is a conceptual diagram illustrating some embodiments of a system 10 to modify human gait kinematics and/or modify muscle activation patterns. The System 10 includes a Housing 20, either flexible or rigid, one or more Affectors 30, one or more Controls 40 in electrical communication with the Affector 30, and one or more Power Sources 50. The Affector 30 can be, for example, an electrical nerve stimulator, vibrotactile stimulator, an implanted electrical nerve stimulator, and/or any device capable of delivering a nerve affecting signal. The Housing 20 can, in some embodiments, include an Interface 60. The Interface facilitates the coupling of the Affector to the subject. For example, the Interface can provide a physical, electrical, and/or chemical connection or point of contact to the subject. Further aspects and embodiments of the present invention are set forth herein. These and other aspects and embodiments of the invention are described in greater detail below, with reference to the drawing figures.

In some embodiments, the device is a wearable device with an electrically conductive skin interface that excites the underlying nerves from a transcutaneous surface stimulator. The device may be sized for a range of user sizes with stimulation electrodes positioned to target the appropriate nerves, as in the device described by International Patent Application No. PCT/US2014/012388, International Patent Application No. PCT/US2015/033809, and

International Patent Application No. PCT/US2016/037080.

In another embodiment, the device and system is a wearable device with an electrically conductive skin interface that excites the underlying nerves from a transcutaneous surface stimulator and has embedded motion sensors (e.g., accelerometers, gyroscopes, magnetometer, bend sensors) and/or force sensors (e.g., strain sensors or pressure insoles) that measure the wearer's gait kinematics (e.g., toe-in angle) and/or kinetics (e.g., ground reaction force or knee joint loads) and store the data to a memory unit either on the device or in a separate unit that communicates via a wired or wireless connection.

In one embodiment as illustrated in FIGS. 2A-2E, the system and device is a wearable unit 200 that includes a wearable strap or band 202 and housing 204 for holding electronics 206. The electronics 206, shown in FIG. 2E can include one or more inertial measurement units (IMU) 208 (e.g., motion sensors such as accelerometers, gyroscopes, magnetometers, bend sensors), force sensors (e.g., strain sensors), muscle and/or nerve activity sensors (e.g., electrodes to measure EMG or microneurography) that communicate with a device control unit that processes measurement data to calculate one or more key gait parameters, such as gait kinematics (e.g., foot-progression angle, knee angle, step width etc.), kinetics (e.g., ground reaction force), muscle activation, or conduction of pain signals to the central nervous system. The electronics 206 can also include a processor 210 and memory 212 for storing instructions, that when executed by the processor, perform the algorithms, calculations, and steps described herein. The memory 212 can also store data gathered by the sensors and store information regarding the use of the device, including how and when the device delivered stimulations or cues to the individual, for example. The electronics 206 can also include a power supply 214 and power regulator 216 to power the various electronic components, and a communications module 218, which can be wireless, to communicate with other sensors, wearable devices, or computing devices such as mobile phones, tablets, or computers.

In another preferred embodiment, the device also houses one or more affectors to provide sensory feedback, which could be in the form of electrical stimulation through electrodes, vibration (e.g., vibration motor), auditory (e.g., speakers or headphones), tactile (e.g., skin stretch), or visual (e.g., LEDs on device, smartphone screen, or glasses).

In some embodiments as shown in FIG. 2F, the device and system includes one or more wearable devices 200 with an electrically conductive skin interface for transcutaneous nerve stimulation, embedded measurement sensors, and sensory feedback units (i.e., cuing, muscle repatterning, and/or sensory augmentation) that notify the wearer of deviations in gait variables. In this embodiment, the device includes two separate units that communicate by wired connection or wireless communication (e.g., low-energy Bluetooth). Gait deviations can be calculated with data from embedded motion sensors and the device control unit. Sensory feedback to the wearer could be in the form of vibrotactile sensation (e.g., vibration motors), auditory sensation (e.g., speakers), tactile sensation (e.g., skin stretch or band tightening), electrical stimulation of peripheral nerves such as the tibial nerve or other sensory nerves, or other standard forms of haptic feedback. The feedback system could also notify the wearer of key events based on analysis of biological measures, including, but not limited to, prediction of pain level increase. The system, which may include cuing, could also notify the wearer of other predetermined events or reminders set by the wearer. An advantage of the system is that information can be communicated to the wearer real-time during activities, such as walking, running, or stair climbing. Instead of or in addition, the device can provide stimulation or modulate the stimulation to retrain gait such that the feedback is provided less frequently or at a decreased intensity level until it is no longer needed, referred to hereafter as fading feedback, as further described herein with respect to stimulation that promotes learning, for example.

In some embodiments, the sensor(s) and affector(s) may be combined into a single device, or they may be separate devices, wherein they are capable of rapid wireless or wired communication, as illustrated in FIG. 2F.

In some embodiments, the wearable unit houses an electrical stimulation unit that is connected to the wearer's skin through an electrically conductive skin interface to provide transcutaneous stimulation. In a further extension, the stimulation unit may have a logic controller that adjusts stimulation parameters (e.g., stimulation amplitude, frequency, waveform, etc.) based on sensor measures and/or calculated gait parameters.

In some embodiments as shown in FIG. 3, the wearable device 300 includes a linear array of stimulation affectors (e.g., electrical or vibrotactile) 302 that are circumferentially distributed in a band that is intended to be worn around the leg, such as the calf, the knee, the ankle, or the thigh. The stimulation affectors are driven in a timed pattern to give the wearer a sense of direction to alter their gait. For example, the affectors could be driven in a clockwise pattern to inform the individual to toe-out while walking, and the motor could be driven in a counter-clockwise pattern to indicate toe-in gait.

In some embodiments as shown in FIG. 4, the system can include a measurement unit 400 and a cuing unit or stimulation unit 402 that are embedded into an insole 404 that is inserted into the individual's shoe. The insole can have pressure sensors, such as strain or piezoelectric sensors, to measure ground reaction pressure or force of the individual, and could have accelerometers, gyroscopes, and magnetometers to measure the position and orientation of the individual's lower limb. The insole can also have an array of stimulation affectors to provide feedback, which may include cuing, to the individual. Affectors could be oriented in two arrays longitudinally on the medial and lateral side of the foot to indicate direction to the individual; or motors could be oriented transversely across the ball of the foot to indicate direction. In some embodiments, the system can have electrodes for providing electrical stimulation, vibration motors for vibrotactile stimulation, or speaker(s) for providing auditory stimulation. The system can also include a battery 406 and electronics as described herein.

In some embodiments, the wearable unit with measurement sensors (e.g. FIG. 2B-D) could be embedded into the sole of a shoe, as shown in FIG. 15. Ideally, measurement sensors that incorporate rigid components (e.g., circuit board or battery) are embedded under the heel, as this location undergoes less strain due to bending of the foot and shoe during gait, as illustrated in FIG. 16.

In some embodiments, the wearable device can use a plurality of sensors to collect, store, and analyze biological measures about the wearer including, but not limited to, motion (e.g., accelerometers, gyroscopes, magnetometer, bend sensors), ground reaction force or foot pressure (e.g., force sensors or pressure insoles), muscle activity (e.g., EMG), cardiovascular measures (e.g., heart rate, heart rate variability), skin conductance (e.g., skin conductance response, galvanic skin response), respiratory rate, skin temperature, and sleep state (e.g., awake, light sleep, deep sleep, REM). Using standard statistical analysis techniques, such as a logistical regression or Naïve Bayes classifier, these biological measures can be analyzed to assess a person's state, such as activity, such as sedentary versus active, and muscle usage, which in turn, can serve as a predictor for increases in pain levels.

In some embodiments, the measurement unit could employ accelerometers, gyroscopes, and/or a magnetometer attached to the individual's foot or ankle or shoe or sock to measure foot progression angle, which can be used to provide feedback to the individual about toe-in/toe-out of their gait. For example, measurement of progression angle can be calculated by taking the difference between foot orientation measured with gyroscopes and a heading direction determined from the magnetometer.

In some embodiments, the measurement unit could employ two sensors or two sets of sensors that measure step width (i.e., the lateral distance between steps) of the individual's gait. Step width could be measured by calculating position of each foot during a step from accelerometers, using a magnetometer to perform a dead reckoning correction of drift of the accelerometer. Step width could also be measured using a sonar or radar system where there is a unit attached to one foot sending and receiving a sonar signal and another unit attached to the opposite foot that reflects the signal; distance between the feet could be estimated as the feet pass by each other during the gait cycle.

In some embodiments, the wearable device can communicate with an external computer or device (e.g., tablet, smartphone, smartwatch, or custom base station) to transmit, store, and process data. Communication between the wearable device and external device can be a direct, physical connection, or with a wireless communication connection such as Bluetooth or GSM or cellular.

In some embodiments as shown in FIG. 5, the device contains a 2D or 3D array 500 of electrodes 502 such that the stimulation may be targeted. The elements of the array, the electrodes 502, may be individually addressable such that the location of stimulation can be adjusted on-the-fly or for each session, such as electronic referencing. Alternatively, the elements may be configured for an individual user, such as a mechanical configuration in which the electrode connections are cut or spliced to customize the device.

In some embodiments, the system communicates with an external, portable computational device, such as a smartphone via an app, or other mobile digital interaction. The device may be used to track information of relevant events either user entered or automatically captured from biological sensors, such as the time since the last knee pain, activity level, or joint load. In a further extension of this embodiment, this information may be used to close the loop to adjust stimulation parameters (waveforms, amplitude, on/off) or suggest user behaviors.

In some embodiments, the system could centrally store biological measures from multiple wearers on a server system (e.g., the cloud), along with other relevant demographic data about each user, including age, weight, height, gender, ethnicity, etc. Data collected from multiple wearers is analyzed using standard statistical techniques, such as a logistic regression or Naive Bayes classifier (or other classifiers), to improve prediction of pain level increases by determining correlations between biological measures, activity level, and other recorded events. These correlations are used to set parameters of the stimulation waveform applied by the stimulation unit, determine best time to apply stimulation therapy, and/or adapt the stimulation waveform applied by the stimulation unit in real time. In addition, these correlations can be used to provide recommendations to the wearer about when to perform therapy or other techniques to reduce pain. In a further extension of this embodiment, the server system can also download and analyze information from the scientific literature to set parameters that adjust stimulation and/or recommendations to the wearer.

In some embodiments, the form of the device could be a knee band, ankle band, sock, knee brace, knee wrap, ankle brace, ankle wrap, shoe or shoe attachment, insole, compliant patch, pants, or a leg sleeve. For example, FIG. 6 shows an embodiment of the device which can include a stimulation and/or sensor unit that can be integrated and/or embedded into a shoe 600. For example, the electronic components 602 can be placed, for example, between the sole 604 and the upper portion 606 of the shoe. Other placement locations on the shoe include the heel or back portion of the shoe, the tongue of the shoe, or the upper portion of the shoe.

In some embodiments, the wearable device can have a processing unit that collects, stores, processes, and analyzes the biological measures, along with other data input by the wearer, such as logging activities or inputting body weight and other user characteristics.

In some embodiments, the wearable device can have a GPS or similar device to track the location and assess activity of the wearer. GPS measures can be combined with mapping or location systems to determine context of the wearer's activity (e.g., gym versus office) or determine changes in elevation during specific activities, such as running or stair climbing.

In some embodiments, the wearable device can track parameters about stimulation provided by the stimulation unit, including time of stimulation, duration of the stimulation session, and power used by the stimulation unit. This data can be stored on memory in the wearable device, processed by the wearable device, and/or transmitted to an external computing device.

In some embodiments, the stimulation unit can use switches or electrical sensor to detect connection of electrodes: to ensure proper and unique electrodes are being installed (i.e., not using a different or incorrect type of electrode) communicating a unique code, for example via RFID; to regulate the number of uses for each electrode to prevent over use; and to prevent the usage of the device without an electrode to prevent small shock.

In some embodiments, the system may include features to increase skin comfort. One solution is to use a high frequency carrier (kHz or greater) wave over the low frequency beats (10 to 200 Hz), or to position electrodes such that the interaction of two waveforms combines to produce a low frequency beat.

In some embodiments as shown in FIG. 7, lidocaine or a similar pain reducing compound (e.g., other analgesics or anesthetics) may be incorporated into an electrode hydrogel 700 to numb the skin surface 702 or desensitize the surface receptors to increase skin comfort. Alternatively, this chemical compound gel could be pushed out from the device similar to how deodorant is snap-clicked out from a deodorant stick, by using a screw mechanism with a plunger 704 that pushes the gel out of the housing 706 through channels 708 in the bottom of the housing that contacts the skin, for example. Another approach is to hypopolarize by initially hyperpolarizing using an excitatory agent like alpha hydroxyl sanshool.

In some embodiments, to improve skin comfort, the skin may be cooled by attaching an outer sleeve containing a cold material, such as a gel, or circulating a cold fluid in pipes housed in the sleeve.

In some embodiments, to improve skin comfort or improve perception of feedback, the wearable device could house a vibration motor to apply a vibrational stimulation simultaneously with electrical stimulation.

In some embodiments, the wearable device has the form of a sock, which is near-field powered by coupling between electronics and coils in the sole of a shoe and a coil in the sock.

In some embodiments as shown in FIG. 8, the wearable device is in the form of a sock, sleeve or other garment that contains an electrode array that can be formed from a crossweave fabric 800 in which a strip along the top or side of the fabric is referenced such that the electrode 802 is positioned at the intersection of the conductive threads, which can have electrical connectors 804 that can be put in electrical communication with a power source.

In some embodiments as shown in FIG. 9, the device is a flexible housing or patch 900 with an adhesive that adheres directly to the wearer's skin. This embodiment has a device with flexible circuitry 902, and a slim, light-weight design to not be cumbersome when worn on the body. Possible locations for the sticky patch could include the foot (either dorsal or plantar side) or on the shank/tibia close to nerves associated with reduction of knee pain, such as the saphenous nerve or tibial nerve. The flexible housing or patch 900 encloses or has a circuit board 904, such as the circuit board described in FIG. 2E and elsewhere, and one or more affectors 906. The affectors are in electrical communication with the circuit board via flexible circuits. The shape of the housing can improve repeatability of positioning the device, for example the widest portion of the housing can be aligned with the long axis of the foot. Additionally the t-shape illustrated allows the affectors to conform around the foot shape and provide physical separation of the affectors to allow distinct perception by the wearer.

In some embodiments, the housing could have a specific shape, for example a t-shape as illustrated in FIG. 9, to allow for easier alignment of the device on the foot, which improves estimation of foot orientation.

In some embodiments, the affectors are disposed in the flexible housing and attached to an electronics board with a flexible circuits FIG. 9, to allow for a flexible housing that conforms to the shape of the body part.

In some embodiments as shown in FIG. 10, the electronics board 1000 with various electronic components 1002 may be rigid and mount to a more flexible or elastic substrate material 1002, such as silicone or rubber, to allow the device to be worn on the body 1006 and conform to different body part shapes.

In other embodiments as shown in FIGS. 11A-11D, the device or system can have many form factors and can include any combination of the form factors described herein. For example, the device could be a fabric garment woven with conductive fabric. Fabric garments can contain electronic fabric with stretch-sensitive fibers for measuring limb position and displacement, and foot pressure, in addition to conductive pathways for electrical stimulation and embedded accelerometers. For example, as shown in FIG. 11A, the device can include a sleeve 1100 wrapped around an extremity, such as a sleeve wrapped around the leg just below the knee. The sleeve can slide on over the leg, or wrap and fasten around the leg with Velcro, snaps, or other common fasteners. FIG. 11B illustrates a flexible device that adheres to the skin like a patch 1102 or bandage, similar to FIGS. 9 and 10, where the device is adhered to the posterior side of the ankle, just above the Achilles' tendon. FIG. 11C illustrates a sock-like fabric garment 1104 worn on the foot. FIG. 11D illustrates a flexible patch 1106 with two electrodes 1108 to target a single nerve. The flexible patch can be coated with a conductive and adhesive hydrogel. The patch can be made of a flexible material, like silicone, to conform to body (e.g., behind knee). The center housing 1110 contains stimulation electronics, sensors, processor, and power source, for example. The housing 1110 may also include a basic user interface 1112 (i.e., one or more buttons) to control stimulation level and/or display information to user. The patch may or may not communicate wirelessly with an external device

In some embodiments the device houses a single affector or a plurality of affectors. Specifically, a single affector would provide feedback to the wearer about a single task or direction (e.g., turn left), while two affectors could provide feedback about two tasks or directions (e.g., turn left or turn right). With two affectors, the affectors need to have enough physical separation to have distinct perception by the wearer. The specific minimum separation distance depends on the specific part of the body where the affectors are applied, the density of sensory receptors, and the type of stimulation. For vibration, a minimum distance can be as low as 15 mm, but preferably between 35-50 mm. Affectors 1200 can also be ordered in an array, for example linear or circular, and activated in specific sequences to convey directionality, as illustrated in FIG. 12.

In some embodiments, the affectors can be stimulated using different specific waveforms to convey a plurality of tasks or actions to the wearer. Waveform parameters that can be varied include amplitude, frequency, pulse width, and duration. Patterns of stimulation bursts can also be used as unique signals. Changes in waveforms need to be varied enough for the wearer to perceive unique sensory feedback signals.

In some embodiments, the device could contain an insole or woven fabric under the foot that can measure force or pressure between the foot and the ground. As shown in FIG. 19, a method to calibrate the orientation 1900 of the foot relative to the wearer's body can include calculating a foot pressure map 1902 from the sensor data after the wearer is instructed to stand in a predefined pose. Key landmarks 1904 from the pressure map 1902 are then identified to estimate the orientation of the foot.

In some embodiments, the wearable unit is in communication, either wired or wirelessly, with a separate stimulation unit that provides transcutaneous stimulation to a location different from that of the wearable unit.

In some embodiments as shown in FIG. 20, the wearable device 2000 has a portable, rechargeable power source, which is near-field powered by coupling between electronics and coils 2002 in the device (i.e., wireless charging) with a wireless charger 2004.

In some embodiments, the wearable unit stores data to a memory unit either on the device or in a separate unit (e.g., tablet, smartphone, smartwatch, or custom base station) that communicates through a wired connection or wirelessly (e.g., low energy Bluetooth or GSM).

In some embodiments, the wearable device can have a processing unit that collects, stores, processes, and analyzes the biological measures, along with other data input by the wearer. In some embodiments, some of the processing of the data can be performed on an external computing device or on the cloud.

In some embodiments, the electrodes for transcutaneous electrical stimulation are dry electrodes made from a conductive materials, such as metallic fabrics or conductive silicone.

The systems, devices, and methods described herein allow the detection or determination of gait variables that are difficult for an individual to detect or sense, such as the adduction moment of the knee, and then provide the individual with sensory stimulation as a proxy for that gait variable, allowing the individual to modify aspects of their motion that are difficult to sense.

Although feedback stimulation can be provided on the leg, ankle, knee, and foot, location of the stimulation can also be positioned on different locations of the body, for example, audio or vibratory stimulation from an individual's smartphone or a smartwatch worn on the wrist.

In addition to the locations of sensors and affectors described elsewhere in this application, FIGS. 24A-24H illustrate other locations where sensors and/or affectors can be positioned. For example, FIG. 24A illustrates positioning a stimulator 2400 on the upper leg and behind the knee using a knee brace 2402 or band or sleeve. FIG. 24B illustrates shorts 2404 with fiber optic sensors 2406. The fiber optic sensor extends from the persons trunk to the knee or joint of interest. The fiber uses three components of strain and twist in order to calculate the relative orientation of the joint of interest based on the detected orientation of the fiber. FIGS. 24C and 24D illustrate placing a sensor 2408 such as an IMU at the back of the heel or on the ankle to determine foot angle. The back of the foot or ankle is more stable than the top or toe portion of the foot. FIG. 24E illustrates placing a stimulator 2400 on the lower leg and behind the knee using a knee brace 2402 or band or sleeve. FIG. 24F illustrates placing a stimulator 2410 on the ankle using an ankle strap 2412. FIG. 24G illustrates the locations to stimulate the superficial peroneal nerve 2413 and the saphenous nerve 2414 on the leg.

FIG. 24H illustrates the locations to stimulate the common peroneal nerve 2416 and the tibial nerve 2418 on the leg.

Method of Altering Gait Kinematics via Sensory Augmentation Therapy

For knee OA, the first peak of the external knee adduction moment (KAM) is often used as a surrogate measure of medial compartment loading and has been correlated with pain and the presence, severity, and progression of medial compartment knee OA. Multiple studies have also shown that individuals with OA can alter their gait kinematics to reduce the first peak of the KAM and reduce knee pain. For example, studies have shown that teaching individuals to walk with a toe-out gait or with a greater step width can reduce the peak of the KAM and/or reduce knee loads. However, these studies were performed in a controlled motion analysis laboratory with expensive motion tracking equipment that requires individuals with OA to return to the lab for training to learn the gait modifications that reduced their KAM. Therefore, in some embodiments, the key gait parameter(s) may be foot progression angle, step width, knee angle or a measure of KAM itself, for example. The systems and devices described herein can be used to determine the key gait parameters.

In some embodiments, the key gait parameter may be foot progression angle, which is defined as the angle between the foot vector and the heading vector (line of walking progression). The foot progression angle is determined in six steps as shown in FIG. 13. Orientation 1300 is estimated via the gradient descent algorithm, trajectory 1302 is estimated via strapdown integration, and stance phase identification 1304 is used with zero-velocity detection to correct velocity estimation drifts. The heading vector 1306 and foot vector 1308 are computed based on results of trajectory and orientation estimation, respectively, and the foot progression angle 1310 is the difference between these vectors in the horizontal plane.

As shown in FIG. 14A, sensor orientation is estimated with respect to the earth frame by integrating angular velocity, from a gyroscope for example, and then applying gradient descent correction with accelerometer and magnetometer data to get drift-reduced orientation estimation.

As shown in FIG. 14B, the foot trajectory is computed through double integration of the acceleration in the earth frame and is corrected via the zero-velocity assumption during stance. Zero-velocity estimation based on acceleration and gyroscope information to help estimate the stance period and implement a state-machine based approach for improved identification accuracy. In addition, heel strike events are detected from the accelerometer and gyroscope and the stance phase duration is approximated as 60% of the stride time.

As shown in FIG. 14C, the foot vector is estimated as the common vector fixed in an IMU-sensor frame. In other words, the foot vector is fixed with respect to the sensor frame S, then is transformed into the earth frame using the corrected orientation estimated from the previous step. Each subject performs dorsiflexion and plantarflexion motion of the ankle to calibrate the device.

As shown in FIG. 14D, the heading vector estimates the direction of forward movement by calculating a foot trajectory at each heel strike by subtracting the current foot trajectory from the foot trajectory at the previous heel strike. To improve heading vector estimation, a complementary filter parameter can also be applied to the foot trajectory at each stride. Finally, the foot progression angle (FPA) is computed as the difference between the heading vector and foot vector integrated over the stance phase of each step. In other words, the foot progression angle is computed as the average angle between the foot vector and heading vector during stance. The foot vector is computed at each time step, while the heading vector is estimated at each stride after heel strike. At each time step, an angle is defined between the foot vector and the heading vector projected onto horizontal plane parallel with the ground, and the foot progression angle for each step is the average of this angle during stance.

The above method was implemented with a wearable sensor and compared to measurements from an optical motion capture system on 13 subjects. The device and method exhibited accuracy similar with the motion capture system.

Step width can also be determined using the procedure described above, using a subset of the parameters and calculations described above.

KAM can be measured by measuring the ground reaction force and determining the position of the parts of leg. For example, the ground reaction force can be estimated or determined based on the body mass of the individual or by direct measurement using sensors in the shoe or bottom of the foot. The position of parts of the leg can be determined by placing and IMU or accelerometer on the upper leg and the lower leg and performing a double integration on the acceleration data to determine position.

In some embodiments as shown in FIG. 17A, the device provides feedback to the wearer when the calculated gait parameter deviates outside of a specified ideal range from step-to-step during gait in two different directions. Providing feedback in this manner can be accomplished with either two affectors or two distinct waveform patterns delivered by a single affector such that the wearer can discern between two different stimulations or cues. As shown, the magnitude of the feedback provided to the individual is related to or proportional to the magnitude of the deviation of the gait parameter from the ideal range.

In an extension of the previous embodiment as shown in FIG. 17B, the device provides feedback to the wearer when the calculated parameter deviates outside of the ideal range in one specific direction. This method for feedback could be useful when changes in gait parameter in only a single direction (e.g., toe-in versus toe-out) affect knee pain, and only requires a single affector delivering a single waveform pattern.

In some embodiments, the feedback can be stimulation to sensory nerves during gait to enhance sensory feedback of knee pain, or of a key variable associated with knee pain, such as foot angle, step width, knee angle, KAM, etc. In some embodiments, the sensory nerves are peripheral nerves located on the leg. In some embodiments, the stimulation may be subsensory, or may be a combination of sensory and subsensory stimulation, such as providing subthreshold electrical stimulation along with an audible or vibratory stimulation. In other embodiments, all the stimulation are above sensory threshold.

In another embodiment, the device is in communication with the affector(s) to apply stimulation to a predetermined or predetermined set or subset of nerves that provide sensory feedback to the central nervous system about pain and a sensor that measures activity of sensory nerves that cause pain (e.g., microneurography) and/or to block or modulate pain signals being sent to the brain. The affector(s) would apply stimulation that is above a threshold to activate sensory nerves, but below a threshold to contract muscle. Activating more sensory nerves associated with knee pain would provide augmented feedback to the central nervous system, which would elicit plastic changes. The affector(s) may be positioned on the femoral nerve to provide both sensory feedback and modulate pain signals, as the femoral nerve is a common site used for post-surgical nerve block. The affector(s) may also be positioned on the saphenous nerve, which is the distal branch of femoral nerve. The saphenous nerve is advantageous for sensory augmentation, as it is a sensory-only (non-motor) nerve. The affector(s) may also be positioned around the ankle to target the two major branches of the tibial nerve that reach the medial and lateral underside of the foot for sensory feedback.

In some embodiments, the device has user input that allows the wearer to input pain levels that is stored on a memory unit. In a further extension of this embodiment, the device adjusts stimulation parameters and/or provides feedback to the wearer based on history of pain levels. This is applicable to modifying muscle activation patterns described below.

In some embodiments, the feedback can be fading feedback such that at the beginning of treatment an enhanced or higher level or magnitude of stimulation is provided to the wearer, but as the treatment progresses, the level or magnitude of the stimulation is reduced as the wearer's gait improves. This promotes quicker learning of the desired gait kinematics that reduce KAM and/or knee pain. For example, FIGS. 17A and 17B illustrate various ways of providing fading feedback as treatment progresses. The dashed lines illustrate fading feedback, while the solid line represents the initial treatment feedback. For example, the feedback level for a given deviation of the gait parameter from the ideal range can be reduced, which is shown in the lower dashed lines. Alternatively, feedback may only be provided to smaller deviations of the gait parameters as treatment progresses, while either keeping the feedback level the same for a given deviation, or increasing the feedback level for a given deviation, or decreasing the feedback level for a given deviation. This is applicable to modifying muscle activation patterns described below.

In some embodiments, individual tuning can be performed. For a particular wearer, a subset of the key parameters may provide effective at altering gait and/or reducing pain while the other parameters may have less or no effect. Therefore, the system, device, and method can track the wearer's gait kinematics improvement over time with each parameter and determine which parameters are most effective for that individual. This is applicable to modifying muscle activation patterns described below.

In some embodiments, the wearer's gait kinematics can be analyzed to determine which gait parameters are likely to be most relevant for a particular individual. For example, the deviations of key gait parameters from the ideal range can be determined, and the parameters with the largest deviations may be selected as the basis for the treatment.

In some embodiments, the wearer may be given different cues or stimulation, such as audio, vibratory, or electrical, to determine which cue or stimulation the wearer responds to the best, which the system and device can select for use during treatment. This is applicable to modifying muscle activation patterns described below.

In some embodiments, the data, which can be stored on the device or on an external device or the cloud, can be analyzed by a health care professional that can then modify the treatment in an open loop manner. The data can be accessed off the device during a follow up visit, by accessing the data on the cloud, or by sending the device back to the manufacturer to extract and transmit the data to the cloud or health care professional. In other embodiments, the system and device can analyze the data itself and modify treatment in a closed loop manner. This is applicable to modifying muscle activation patterns described below.

Method of Modifying Muscle Activation Patterns

In another embodiment, the wearable unit is in communication with an electrical stimulation unit that applies stimulation to a predetermined or predetermined set or subset of muscles that affect gait pattern (e.g., soleus, gastrocnemius, quadriceps) and a sensor unit that measures muscle activity (e.g., electromyogram (EMG)). The simulation unit and the sensor unit can be separate units in communication, wired or wireless, or housed in the same unit as shown in FIG. 18. For example, as shown in FIG. 18, an embodiment of the device that houses electrodes for EMG sensing 1802 and muscle stimulation 1800. The device can attach to the skin using an adhesive hydrogel 1804. The device can be applied to multiple locations on the lower extremity, including, but not limited to, the top of the foot, the head of the gastrocnemius, or above the knee across the quadriceps muscle group. Similar to devices and methods described below, the stimulation can be proportionally controlled based on measurements of voluntary EMG.

Reducing knee pain can be accomplished by reducing the load on the knee. Muscle forces are a large contributor to knee loads during walking, as shown in FIG. 21. Altering muscle forces during gait may reduce knee loads. For example, the gastrocnemius muscle is one of the largest contributors to knee load during walking, especially during late stance, and thus reducing the activation of the gastrocnemius muscle during late stance can reduce knee loads. In some embodiments, the load on the knee can be reduced by reducing an individual's activation of the gastrocnemius muscle, which extends from the femur to the heel and causes compression of the knee when it contracts, and optionally increasing an individual's activation of the soleus muscle, which extends from the tibia to the heel, does not cause compression of the knee when it contracts. FIGS. 22A-22C illustrate the location of the gastrocnemius 2200 and soleus 2202 muscles on the leg with respect to the knee 2204.

Since it is difficult for an individual to detect or control contraction of the gastrocnemius muscle relative to that of the soleus muscle, an EMG sensor can be used to detect and monitor contraction of the gastrocnemius and soleus muscles. When the EMG sensor detects use of the gastrocnemius muscle, feedback can be provided so the individual can reduce usage of the gastrocnemius muscle. When the EMG sensor detects use of the soleus muscle, a different feedback can be provided so the individual can increase the usage of the soleus muscle. The feedback can be detectable stimulation which can be auditory, vibratory, or electrical, for example. If EMG sensors are placed over both the gastrocnemius and the soleus, the two feedbacks can be different so that they are distinguishable by the individual. The feedback can be responsive and/or fading feedback as described herein with respect to FIGS. 17A and 17B. Such a system, device, and method provides motor learning or reprogramming therapy that can either train an individual to increase the use of the soleus and decrease the use of the gastrocnemius, or increase the excitability of the soleus and decrease the excitability of the gastrocnemius during gait, thereby reducing knee load.

In some embodiments, the system, device, and method can provide repetitive stimulation, which may be continuous for a period specified by the user (e.g., patient controlled on/off) or may be applied during a specific time of the day (i.e., daytime or known or scheduled activity period), to a desired muscle or muscles, such as the soleus, to enhance and increase the usage of this muscle during gait and/or to decrease or inhibit or reduce the usage of a muscle, such as the gastrocnemius, during gait. The stimulation can be timed with key gait events such as foot strike, toe off, early stance phase, and late stance phase, for example, which can be detected in real time by sensors during the gait cycle as described herein. Sensors can include EMG, IMU, or pressure sensors in the shoe or insoles or on the base of the foot, for example.

In some embodiments, the stimulation to inhibit or enhance the usage of muscles can be applied as constant or time stimulation during specific or predetermined activities that actively and/or passively engage the muscles of interest, such as stimulation of the tibial nerve and/or stimulations to identify gastrocnemius and soleus usage during exercise that engages the calf muscles, such as toe-raise exercises.

In some embodiments, a muscle or group of muscles can be inhibited or have its excitability reduced, such as the gastrocnemius, instead of or while the other muscle, such as the soleus, is optionally stimulated, in a reciprocal inhibition manner. For example, high frequency stimulation at the neuromuscular junction of the gastrocnemius can decrease the excitability of corticospinal tracts and lead to inhibition of the gastrocnemius and reduced knee load during walking. In some embodiments, the excitability of the gastrocnemius can be decreased by high frequency stimulation of a peripheral nerve such as the sciatic or tibial nerve to decrease excitability of its corticospinal tracts. In some embodiments, the excitability of the soleus can be increased by repeated peripheral stimulation of the tibial nerve. In some embodiments, the excitability of the soleus can be maintained or increased by exciting the peroneal nerve behind the knee or exciting the sural nerve in order to increase excitability of soleus motor neuron pool (as measured by means of the Hoffman reflex, or H reflex).

In some embodiments, the system, device, and method can alter gait kinematics and modify muscle activation for a combined treatment approach. This combined approach is particularly advantageous because changes in gait kinematics tend to have a greater effect on the peak knee load during the early stance phase (load generated after foot strike), which is shown as the first peak in FIGS. 23A and 23B, and changes in muscle generated force tend to have a greater effect on the peak knee load during the late stance phase (load generated prior to toe off), which is shown as the second peak in FIGS. 23A and 23B. FIG. 23 illustrates a reduction in knee load due to altering gait kinematics. Reduction is seen in the first peak of the curve during early stance. FIG. 23B illustrates a reduction in knee load due to reduction of muscle activation of gastrocnemius. Reduction is seen in the second peak of the curve during late stance.

Overall Framework

Treatment of a patient with knee pain from OA can be broken down into three phases: (1) diagnosis of the patient, (2) determining treatment based on the diagnosis, and (3) providing the treatment to the patient.

Diagnosis can include performing a diagnostic assessment of the patient using the wearable sensors described herein, such as IMU, accelerometers, pressure sensors, and EMG, to determine various gait parameters and muscle activation patterns, such as foot angle, knee angle, KAM, step width, gastrocnemius activation, and soleus activation. The patient can be provided (e.g., mail or pick up at doctor's office) with a kit with sensory prosthetics (e.g. wearable sensors) and optionally a video camera. In addition, video taken from a mobile phone or other camera (i.e., webcam, Kinect) can also be used to determine various gait parameters. During diagnosis, instructions can be provided to the patient to perform a predetermined series of tasks or actions, such as walking and/or toe raises, while using the sensors and/or video. Values and/or percentages can be assigned to each parameter or characteristic in order quantify its importance, which may be based on its magnitude or degree of deviation from an ideal range or value (degree of abnormality). The values and/or percentages can be used to identify and/or prioritize which parameters or characteristic needs the most correction. The patient can wear and use the sensors during the diagnostic phase for a predetermined or prescribed period of time (day, week, other interval). Data from the sensors can be uploaded to the cloud or another computing device, or the sensors can be sent back to the manufacturer for data analysis and then refurbished for a new patient.

The appropriate treatment for each patient can be determined based on the data generated by the diagnosis by a health care provider or by the processor unit of the system and device or by an external computing system. For example, high use of the gastrocnemius identified during diagnosis may indicate that the system and device should focus on training the patient to reduce use of the gastrocnemius. The diagnosis may also indicate that foot angle needs correction, but at a lower priority than gastrocnemius correction. In some embodiments, the treatment can be prescribed to focus on modifying one parameter or characteristic at a time, based on the priority identified during diagnosis, because it may be difficult for a patient to work on changing multiple parameters or characteristics simultaneously. In addition, working on a single parameter or characteristic may only require providing a single stimulation or cue, while working on multiple parameters or characteristics simultaneously would require providing multiple stimulations or cues that can be distinguished by the patient. The stimulation dosing can be optimized to promote or enhance motor and/or neural entrainment, using for example, responsive or proportional feedback/stimulation and/or fading feedback.

Once the treatment plan has been determined, the patient can be provided (e.g., mail or pick up at doctor's office) with the appropriate treatment system and device, which can be programmed to execute the treatment plan. The patient can be instructed, on a mobile phone app for example, on how and where to place the various components of the system and device on the patient's body. In some embodiments, the initial kit can include both the diagnostic sensors and treatment system and device, or the initial kit can include a system and device that performs both the diagnostic and treatment functions. In some embodiments, the system and device is designed to operate for a predetermined length of time, such as up to 30, 60, or 90 days, at which point the patient exchanges the old system and device with a new system and device. The old system and device can be returned to the manufacturer for refurbishing.

When a feature or element is herein referred to as being “on” another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being “directly on” another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being “connected”, “attached” or “coupled” to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being “directly connected”, “directly attached” or “directly coupled” to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.

Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms “upwardly”, “downwardly”, “vertical”, “horizontal” and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

Although the terms “first” and “second” may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods and articles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word “about” or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and/or position to indicate that the value and/or position described is within a reasonable expected range of values and/or positions. For example, a numeric value may have a value that is +/−0.1% of the stated value (or range of values), +/−1% of the stated value (or range of values), +/−2% of the stated value (or range of values), +/−5% of the stated value (or range of values), +/−10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that “less than or equal to” the value, “greater than or equal to the value” and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value “X” is disclosed the “less than or equal to X” as well as “greater than or equal to X” (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. 

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 24. A method for reducing knee pain associated with osteoarthritis in an individual, the method comprising: measuring a gait parameter; determining a deviation of the measured gait parameter from a set range or value for the gait parameter; delivering a sensory stimulation to the individual based on the determined deviation of the measured gait parameter; and altering the individual's gait kinematics such that the deviation of the measured gait parameter is reduced in subsequent measurements of the gait parameter.
 25. The method of claim 24, wherein the gait parameter is selected form the group consisting of foot angle, step width, knee angle, and knee adduction moment.
 26. The method of claim 24, wherein the set range or value is predetermined.
 27. The method of claim 24, wherein the sensory stimulation is delivered in a fading feedback manner.
 28. The method of claim 24, wherein the sensory stimulation is electrical and is configured to not induce contraction of a muscle.
 29. The method of claim 28, wherein the electrical sensory stimulation is configured to enhance motor plasticity.
 30. The method of claim 24, further comprising: measuring an activation of the gastrocnemius muscle; and delivering a second sensory stimulation based on the activation of the gastrocnemius muscle to inform the individual of the activation of the gastrocnemius muscle.
 31. The method of claim 30, further comprising: measuring an activation of a soleus muscle; and delivering a third sensory stimulation based on the activation of the soleus muscle to inform the individual of the activation of the soleus muscle.
 32. The method of claim 24, further comprising delivering a stimulation configured to reduce an excitability of the gastrocnemius muscle.
 33. The method of claim 24, further comprising delivering a stimulation configured to enhance an excitability or activate a soleus muscle.
 34. The method of claim 24, further comprising: measuring an activation of the gastrocnemius muscle; measuring an activation of a soleus muscle; delivering a second sensory stimulation based on the activation of the gastrocnemius muscle to inform the individual of the activation of the gastrocnemius muscle; delivering a third sensory stimulation based on the activation of the soleus muscle to inform the individual of the activation of the soleus muscle; delivering a stimulation configured to reduce an excitability of the gastrocnemius muscle; and delivering a stimulation configured to enhance an excitability or activate a soleus muscle.
 35. A method for reducing knee pain associated with osteoarthritis in an individual, the method comprising: measuring a plurality of gait parameters; determining a deviation of each of the measured gait parameters from a set range or value for each of the gait parameters; prioritizing the plurality of gait parameters based on the determined deviations; identifying a high priority gait parameter based on the step of prioritizing the plurality of gait parameters; delivering a sensory stimulation to the individual based on the high priority gait parameter; and altering the individual's gait kinematics.
 36. The method of claim 35, wherein the sensory stimulation is delivered to a peripheral nerve in the leg.
 37. The method of claim 35, wherein the sensory stimulation is delivered to a sensory nerve in the leg.
 38. A method for reducing knee pain associated with osteoarthritis in an individual, the method comprising: measuring a plurality of gait parameters; measuring activation of the gastrocnemius muscle; determining a deviation of each of the measured gait parameters from a set range or value for each of the gait parameters; prioritizing the plurality of gait parameters based on the determined deviations; identifying a high priority gait parameter based on the step of prioritizing the plurality of gait parameters; comparing the identified high priority gait parameter with the measured activation of the gastrocnemius muscle; delivering a sensory stimulation to the individual based on the comparison of the high priority gait parameter with the measured activation of the gastrocnemius muscle; and altering the individual's gait kinematics or muscle pattern activation.
 39. The system of claim 38, wherein the sensory stimulation comprises a stimulation parameter selected from the group consisting of: amplitude, frequency, pulse width, duration, and waveform shape. 